This problem related to Earth fault protection scheme for Transformers. The Fig.1 is Line to Line short circuit fault, Fig.2 is Line to ground short circuit fault and Fig.3 is Line to line to Ground short circuit faults. Please find out the current flowing through the Resistor R7( fault current ) for 3-cases.

Note: A. The transfromer ratio is 1:10
B. The transformer is Star-Star winding type. C. See the attachement for refering the figer ( fig.1, fig.2, and fig.3 )